1. Field of the Invention
The present invention relates to a solid state image pickup device and signal reading method thereof, and more particularly to a solid state image pickup device having a drive mode for reading all pixels, a drive mode for reading pixels by skipping some pixels, and a plurality of read-out systems for reading pixels.
2. Related Background Art
In a solid state image pickup device having a plurality of solid state image pickup elements constituting a plurality of pixels, in order to read signals from pixels at high speed and eliminate the restrictions on mounting elements on a substrate or the like, a plurality (e.g., two) of read-out systems are provided to divisionally read signals from the pixel array at the same time.
Such a solid state image pickup device can read signals at high speed, and since the read-out systems can be disposed separately, the restrictions on mounting elements on a substrate can be eliminated. Regardless of these and other advantages, however, a power consumption increases because of provision of a plurality of read-out systems, and signal outputs from the read-out systems may include difference therebetween due to a variation in characteristics of elements of the read-out systems.
An object of the invention is to reduce a power consumption of a solid state image pickup device.
Another object of the present invention is to suppress a variation in output signal levels, caused by a variation in characteristics of elements of a solid state image pickup device.
In order to achieve the above objects, according to a preferable embodiment of the invention, there is provided a solid state image pickup device comprising: driving means having an all pixel drive mode for reading all pixels in a horizontal direction and a pixel skip drive mode for reading pixels in the horizontal direction by skipping some pixels; and a plurality of read-out systems for reading pixels, wherein in the all pixel drive mode, signals of pixels are divisionally read by the plurality of read-out systems, and in the pixel skip drive mode, signals of pixels are read by one of the plurality of read-out systems.
According to another embodiment of the invention, there is provided a solid state image pickup device comprising: driving means having an all pixel drive mode for reading all pixels in a horizontal direction and a pixel skip drive mode for reading pixels in the horizontal direction by skipping some pixels; a plurality of read-out systems for reading pixels; and switching means for connecting pixels connected to at least one read-out system to another read-out system, wherein in the all pixel drive mode, signals of pixels are divisionally sent to the plurality of read-out systems, and in the pixel skip drive mode, signals of pixels connected to at least one read-out system are sent to the other read-out system by using the switching means.
According to another embodiment of the invention, there is also provided a signal reading method for a solid state image pickup device having a plurality of read-out systems for reading pixels, comprising an all pixel drive mode for reading all pixels in a horizontal direction, and a pixel skip drive mode for reading pixels in the horizontal direction by skipping some pixels, wherein in the all pixel drive mode, signals of pixels are divisionally read by the plurality of read-out systems, and in the pixel skip drive mode, signals of pixels are read by one of the plurality of read-out systems.
According to another embodiment of the invention, there is also provided a signal reading method for a solid state image pickup device having a plurality of read-out systems for reading pixels, comprising an all pixel drive mode for reading all pixels in a horizontal direction, and a pixel skip drive mode for reading pixels in the horizontal direction by skipping some pixels, wherein in the all pixel drive mode, signals of pixels are read by using the plurality of read-out systems in parallel, and in the pixel skip drive mode, signals of pixels connected to at least one of the plurality of read-out systems are read by using another of the plurality of read-out systems.
Other objects and features of the invention will become apparent from the following specification and drawings.